Recent observations show that spiral galaxies are surrounded by massive and extended haloes of both neutral and ionized gas. These gaseous haloes have peculiar kinematics with respect to their discs: they rotate more slowly and they show an overall inflow motion. Theoretical models of the formation of these gaseous haloes show that they cannot originate solely from a galactic fountain (supernova outflows from the disk); substantial accretion of material from the Intergalactic Medium should play an important role.

Observations of young low-mass binaries (t ≲ 107 yr, M ≲ 3 M_⊙) can be used to calibrate pre-Main Sequence (pre-MS) evolutionary tracks. Recent high angular resolution HST/FGS, speckle, and long-baseline interferometry have resolved the astrometric orbits of a few SB2 pre-MS binaries and have provided the individual dynamical masses of their components as well as the system orbital parallaxes. Spectroscopic fits and filter photometry have permitted to determine SpT (temperatures) and a good estimate of the absolute magnitude (bolometric luminosity) of the components, which in turn allows one to place the components on a theoretical HR-diagram. In this way, one can check (a) whether the measured dynamical masses agree with the predicted masses on the tracks and (b) whether both components lie on an isochrone, as they should for a coeval physical pair of stars.

With a sufficiently large sample of different masses and ages of resolved SB2 systems, most of the parameter space of pre-MS tracks can be tested, even for very low stellar masses (M < 0.5 M_⊙) and very young ages (< 2 Myr). This is a prerequisite in order to derive the IMF and star formation history in very young clusters and associations.

Using the ASAS-3 photometry, we find the components of four eclipsing binary systems — V916 Cen, HD 101838, V4386 Sgr and HD 168050 — to be β Cephei-type pulsators. The first two systems are members of the young open cluster Stock 14. The pulsating stars are presumably the primary, more massive components in all these systems. The components are detached and for at least two systems, V916 Cen and HD 168050, we may suspect that they will appear to be double-lined spectroscopic ones. In consequence, these stars become very attractive targets for studying pulsations in β Cephei stars by means of asteroseismology.

We examined observational characteristics of multi-phase turbulent flows in the diffuse interstellar medium (ISM) by calculating atomic and molecular carbon lines. Radiation field maps of C+, C0, and CO line emissions were generated by calculating the non-local thermodynamic equilibrium (nonLTE) level populations and high resolution hydrodynamic simulations of diffuse ISM. By analyzing synthetic line emission, we found a high ratio between the lines of high- and low-excitation energies in the diffuse multi-phase interstellar medium. Our results shows that simultaneous observations of the lines of warm- and cold-gas tracers will be useful in examining the thermal structure, and hence the origin of diffuse interstellar clouds.

Young brown dwarfs have been identified in a significant population in various star forming regions. Some deep surveys have yielded less massive objects with planetary-mass (e.g., Oasa et al. 1999; Lucas & Roche 2000). Nevertheless, it is not yet clear how abundant these very low-mass objects are formed. S106 is one of the nearest massive star-forming regions associated with prominent bipolar nebulae and an HII region. We have conducted near-infrared photometric and spectroscopic observations of very low-mass young stellar objects (YSOs) in the S106 region.

Since 2005, the workflow working group of OV-France gathers astronomers from five french institutes with common objectives: (i) defining use cases of general interest; (ii) identifying the simplest workflow structure allowing portability; and (iii) suggesting solutions for designing and exploiting easily such workflows (cf. Astrogrid developments). Our workflow definition is the following: a sequence of tasks executed within a controlled context by an architecture taking into account VO standards.

Blue compact dwarf (BCD) galaxies are low-metallicity objects undergoing violent star formation (Searle & Sargent 1972). We present our ongoing work on integral field spectroscopy (IFS) of the two prototypical BCD galaxies IIZw70 and IZw18 (Papaderos et al. 2002). Two-dimensional spectroscopy allows us to collect simultaneously the spectra of many different regions of an extended object, combining photometry and spectroscopy in the same data set. The great advantage of using IFS for the investigation of galaxies is that it allows us to obtain data on the galaxies' positions, velocity fields and star-forming properties all in one data cube. The observations were taken with the instruments INTEGRAL/WYFFOS at the WHT (ORM, La Palma) and PMAS installed on the 3.5m telescope at the CAHA, covering a spectral range from λ 3600 to 6800 Å. The data are mainly used to study the ionized gas and stellar clusters. Our main goal is to investigate the presence of spatial variations in ionization structure indicators, physical conditions and gaseous metal abundances, in these galaxies (Vílchez & Iglesias-Páramo 1998). We also study the kinematical properties of the ionized gas, as well as systematic variations of ionization structure and physical-chemical parameters as a function of the surface-brightness in Hα emission. Maps of the relevant emission lines are presented.

VLA A-array snapshots were obtained of a complete sample of steep-spectrum radio sources from the Texas Radio Interferometer survey. Though similar in sensitivity to the FIRST Survey, our A-array snapshots have better resolution, and are complementary to FIRST. All initial A-array maps are made, and we are comparing them to FIRST.

We examine the intensity of scattered near-infrared (NIR) light in the case of interstellar clouds illuminated by the normal interstellar radiation field. We have developed a way to convert the observed surface brightness into estimates of the column density and have estimated the accuracy of the new method. The NIR intensities can be converted into reliable estimates of the column density in regions with AV up to almost 20 magnitudes. The errors can be further reduced with detailed radiative transfer modelling and by using the lower resolution information that is provided by the colour excess data of background stars. Therefore, NIR scattered light is a promising new way to map quiescent interstellar clouds at a high, even sub-arcsecond resolution.

A remarkable variety of particle acceleration occurs in the solar system, from lightning-related acceleration of electrons to tens of MeV energy in less than a millisecond in planetary atmospheres; to acceleration of auroral and radiation belt particles in planetary magnetospheres; to acceleration at planetary bow shocks, co-rotating interplanetary region shocks, shocks driven by fast coronal mass ejections, and possibly at the heliospheric termination shock; to acceleration in magnetic reconnection regions in solar flares and at planetary magnetopause and magnetotail current sheets. These acceleration processes often occur in conjunction with transient energy releases, and some are very efficient. Unlike acceleration processes outside the solar system, the accelerated particles and the physical conditions in the acceleration region can be studied through direct in situ measurements, and/or through detailed imaging and spectroscopy. Here I review recent observations of tens of MeV electron acceleration in the Earth's atmosphere and in the Earth's radiation belts, electron and ion acceleration related to magnetic reconnection in solar flares, electron acceleration to ≥ 300 keV in magnetic reconnection regions in the Earth's deep magnetotail, and acceleration of solar energetic particles (SEPs) by shocks driven by fast coronal mass ejections (CMEs).

Numerous new Solar System objects, mainly asteroids, are still detected nowadays but their physical and dynamical characteristics remain not accurately determined, until dedicated observations and analysis are made. However, the Virtual Observatory is a perfect framework to search for this characterization by data mining. We are developing two studies for this goal by exploring the DENIS infrared and DFBS spectroscopic surveys. In order to scan the survey catalogues and to search for Solar System objects, we have developed a VO compliant workflow founded on the use of a recent VO tool labelled SkyBoT (Sky Bodies Tracker) (Berthier et al. 2005) and on the VizieR service provided by CDS. A public version of SkyBoT is implemented in the sky atlas Aladin since January 2006. It allows us to quickly get the precise coordinates of the asteroids, planets and natural satellites in any star field, provided we know its center, its size and the precise date of the exposure (between 1949 and 2009). Our data mining workflow performs cone search queries on SkyBoT and VizieR to extract all the known astronomical objects observed by the survey. Then the sources which are detected in the survey are correlated with the known objects to determine the matched and unmatched objects.

We have been conducting PISCES project (Panoramic Imaging and Spectroscopy of Cluster Evolution with Subaru; Kodama et al. 2005) with making use of the wide-field imaging capability of Subaru. Our motivations are first to map out large scale structures and define local envioronments of galaxies therein, and then to investigate the variation in galaxy properties as a function of environment and mass. We have completed multi-colout imaging of 8 distant clusters between 0.4 < z < 1.3 so far, and we have mapped out filamentary/clumpy structures in and around the clusters across 15–30 Mpc scales (see some examples in Fig. 1). These two clusters have secure spectroscopic confirmation of the physical association of the structures to the main body of the clusters. From the photometric and spectroscopic properties of galaxies over a wide range in environment, we have found that the truncation of galaxies is seen in the outskirts of clusters rather than in cluster cores. We have also seen a clear environmental dependence of the “down-sizing” in the sense that the stage of down-sizing is delayed in lower density environments.

We report the preliminary results of the study on the infrared properties of ultracompact (UC) H II regions in our Galaxy and in the Large Magellanic Cloud (LMC) based on the GLIMPSE (the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) and SAGE (Surveying the Agents of a Galaxy's Evolution) data, respectively. We found that ~60% of the Galactic UC H II regions do not have IR counterparts. Large extinction and very strong stellar winds evacuating H II regions from dust may explain this result. The same effect is observed in the LMC. One of the goals of this research is to develop a means of identifying UC H IIs based on their mid-IR properties, e.g. positions on color-color and color-magnitude plots and/or shape of spectral energy distributions. GLIMPSE showed that bow shocks, protostellar jets/outflows, and bubbles are common phenomena in massive star formation regions (MSFRs).

During the last few years, Thailand has seen a significant change in the way astronomical research and education is pursued in the country. The government has approved the establishment of the National Astronomical Research Institute of Thailand (NARIT) which aims to develop not only astronomical research but also astronomy education at all levels, both in formal and informal education. A framework of national key projects exists which includes national facilities, national collaborative research networks, teacher training and public outreach programmes. Examples of these programmes will be presented in this paper.

The Virtual Observatory is one of the very few truly global endeavours of astronomy, and IAU General Assemblies are the natural places to present the VO to the community. The three-year time scale of IAU is also well suited to measure progress. At the IAU XXV GA in Sydney, 2003, half of the two-day Joint Discussion 8 on Large Telescopes & Virtual Observatories: Visions for the Future was devoted to VO talks: the main goal was to review what was expected from the VO in different disciplines of astronomy; many projects were also presented in the poster sessions. This time the three-day VO Special Session has given an excellent overview of present status of the VO, showing both tremendous progress and the work which remains to be done. Several scientific communities (astronomy, solar and heliospheric physics) are working on VO development, national communities have been organizing themselves in VO projects. Implementation by data centres has begun. Additional technical development is required, and there are still technical challenges. There is also a huge work ahead for providing high quality data and services, but the VO development already has a very positive influence on astronomers' work environment, and more is to come.

Excitation of solar-like oscillations is attributed to turbulent convection and takes place at the upper-most part of the outer convective zones. Amplitudes of these oscillations depend on the efficiency of the excitation processes as well as on the properties of turbulent convection. We present past and recent improvements on the modeling of those processes. We show how the mode amplitudes and mode line-widths can bring information about the turbulence in the specific cases of the Sun and α Cen A.

We present a review of the Division I Working Group on Precession and the Ecliptic.

The statistical algorithm MEMPHIS (Cubarsi & Alcobé 2006) was applied to a large sample from the Hipparcos catalogue with the full space motions (Cubarsi & Alcobé 2004), to segregate the kinematic populations of the solar neighbourhood. Four stellar populations were obtained, namely early-thin disk, young-thin disk, the whole thin disk (which contains both previous populations plus the continuum of old thin disk stars), and the thick disk population. Now, we wish to point out two main results from the analysis of such a segregation (Alcobé & Cubarsi 2005). First, the relationship between the maximum stellar velocity of a sample and its average age τ can be approximated by the relation |V|max ∝ τ. Second, the local stellar populations can be described from a Titius-Bode like law (TBLL) for the radial velocity dispersion, , so that for values n = 2, 3, 5, 8 it determines some average energy levels of discrete populations, while for continuous intervals n ≤ 5 and n ≥ 7 it describes the velocity-age evolution of thin and thick disk components, as shown in the Table below.

Thus, the velocity dispersions of the local kinematic populations seem to follow a geometrical progression, allowing us to do an analogy with the old Titius-Bode distribution for keplerian orbits, although a physical explanation for the later law remains still open (Lynch 2003). Indeed, such a TBLL in the velocity space could be already conjectured from previous published kinematic parameters of the Galactic components (e.g. Alcobé & Cubarsi 2001). As in the keplerian case, it is possible to argue that velocity dispersion values have too much uncertainty, but, even so, it is not possible to ignore anymore such a resemblance.

Such results are consistent with Galactic formation models that predict some quasi-continuous stellar populations in the sense that the continuity is constricted by σ1 levels of the TBLL. The physical meaning of the variable n involved in the TBLL may be related with the average epicycle energy ER ~ σ21 of the stars representative of the disk heating process. It shows continuity from n = 3 to 5 for the thin disk, and from 7 to 8 for the thick disk, but discreteness from n = 2 to 3 between early-thin and young-thin disk, and from 5 to 8 between thin and thick disk components. For the thin disk, for example, the level n = 5 should represent the saturation point of maximum velocity dispersion, likely corresponding to the limited predicted by the observed wavenumber of spiral structure of the Milky Way, while the discontinuity from n = 5 to 7 indicates an abrupt jump in the average energy, that was produced when the thick disk was formed about 10±1 Gyr ago.

Figure 1.

Schematic presentation of our new chemo-dynamical tool. See Champavert & Wozniak (2007a) for full details and references.